OpenSMTPd seems easier superficially but it's not particularly well-documented. I don't remember the details but I remember struggling with setting it up becaus

OpenSMTPd seems easier superficially but it's not particularly well-documented. I don't remember the details but I remember struggling with setting it up because certain config flags were not documented and I had to guess their exact meaning from the few blog posts out there that discuss OpenSMTPd. (It also didn't help that there were slight changes in the config format at some point in the past.)